I was trying to teach my Jarizmo the move "Cast-Over" which is the first move it would learn from leveling. I used a move relearner on him, and when I fought a battle, it skipped right over the move and he couldn't relearn it.

I believe the problem is that because it would technically be his lv 1 starting move, and that technically speaking, he would never actually have to level up to learn the move. As a result, move relearner also doesn't include this first move in the list of moves you can relearn.

I tested on some other monsters and confirmed that for any monster you use move relearner on, the monster CANNOT relearn the first move listed on their 'level-up attacks' list.

The arrogance of success is to think that what you did yesterday will be sufficient for tomorrow.